Electric switch.



TATBNTED AUG. 4, v190A.

No. 735,452.l

W. L. BLISSrx ELECTRIC SWITCH.

APPLICATION FILED TBB. 26, 1902.

No MODEL.

UNITED STATES Patented August 4, 1903.

PATENT OEEICE.

WILLIAM LORD BLISS, OF BROOKLYN, NEW YORK, ASSIGNOR TO BLISS ELECTRIC CAR LIGHTING COMPANY, OF NEW YORK, N. Y., A COR- PORATION OF NEW JERSEY.

ELECTRIC SWITCH.

SPECIFICATION forming part of Letters Patent No. 735,452, dated August 4, 1903.

Application filed February 26,1902. Serial No. 95,739. (No model.)

To all whom it may concern,.-

Be it known that I, WILLIAM LORD BLIss, a citizen of the United States, and a resident of the borough of Brooklyn, in the city and State of New York, have invented anew and useful Improvement in Electric Switches, of which the following is a specification.

My invention relates to an improvement in electric switches, and has for its object to provide an automatic switch which will be under the control of a motiveuid-such, forinstance,as compressed air-whereby the switch is closed under pressure and opened by the release of the pressure.

A further object is to provide certain improvements in the construction, form, and arrangement of the severalparts of the switch, whereby the switch will be simple and positive in operation, in which the cylinder will be self-sealing, so as to prevent the escape of the motive fluid, and in which the parts are well protected, thus rendering the switch particularly applicable for use where it is subjected to rough treatment.

This switch is particularly applicable for use in connection with car-lighting systems, wherein'it is connected to the pneumatic signal-pipe of the car and is controlled thereby for making and breaking electrical circuits in the lighting system.

A practical embodiment of my invention is represented inthe accompanying drawings, in which* Figure 1 is a view of the switch in side elevation. Fig. 2 is a vertical central section through the same, the switch being shown open as when the pressure is withdrawn from the piston; and Fig. 3 is a top plan view of the switch with the contact-plate protecting cap or cover removed.

The cylinder of the switch is denoted by 1, and the piston-chamber therein by 2. The piston-chamber 2 is connected to a fluid-pressure pipe 3, which may be the train signalpipe of a car. A cock 4 is interposed between the pressure-pipe 3 and cylinder 1 for positively controlling theadmission of fluidpressure to the interior ofthe cylinder. When the pressure-supply pipe 3 is the signal-pipe 5o of a railway-car, it must never be opened to the atmosphere except by special apparatus for that purpose. (Not shown.) The cock 4 serves to close the pressure-supply pipe 3, thus permitting the removal of the switch for repairs or other purposes. The cock 4 may be a simple straight cock or a three-way cock having a vent to relieve the pressure in the cylinder 1 when said cock is turned so as to close the pressure-supply pipe 3. A coupling or union 5 of' usual form connects the cock 4 with the hollow lug 6, depending from the bottom of the cylinder l, the bore 7 through the lug opening into the bottom of the piston-chamber 2. A lining tube or bushing 8 is itted within the piston-chamber 2, from its top to a point about half-way down within the chamber, for engaging the periphery of the hollow piston-head 9 of the piston, which is located within the piston-chamber. A cylinder-head 10 serves to close the upper end of the piston-chamber within the cylinder 1, which head is secured in position by means of' bolts 11 and l2, which pass through lugs 13 and ll on the cylinder-head and lugs 15 and 16 on the cylinder. The heads of these bolts 11 and 12 are developed into binding-posts 17 and 18 below the lugs l5 and 1G upon the cylinder for the attachment of the circuit-wires of the switch. These bolts 11 and 12 are insulated from the lugs 13 14 15 16 by the flanged tubes 19 20, of fiber or other suitable insulating material.

Contactplates 21 22 are secured to thc bolts 11 and 12 in the following manner: These contact-plates 21 22 have laterally-extended portions or bases 23 24, which embrace the ends of the bolts 1l and 12, which project above the lugs 13 and 14 of the cylinder-head, between which bases and the tops of the said lugs are interposed insulatingwashers 25 2G, of mica or other suitable insulating material. The nuts 27 28, which engage the screw-threaded ends of the bolts 1l and 12, serve not only to clamp the contactplates 21 22 in position, but also serve to clamp the cylinder-head 10 in its position with respect to the cylinder.

rlhe upwardlyextended portions of the contact-plates 21 22 are brought inwardly toward each other and preferably are curved in cross-section and slotted to insure a good contact with the connecting-disk 37, carried by the piston, to bc hereinafter described.

To hold the contact-plates against displacement by swinging around on the bolts when the switch is subjected to severe jars or when the nuts 27 and 2S become loosened, I provide the cylinder-head lO with four lugs 29 30 3l 32. The contact-plate 2l is retained in position between the lugs 29 and 30, and the contact-plate 22 is retained in position between the lugs 3l and 32.

The insulating-washers 25 and 26 are bent up on each side so as to interpose insulation between the contact-plate 2l and the lugs 29 and 30 and between the contact-plate and the lugs 3l and 32.

A packing-ring or gasket 33 is interposed between the cylinder-head lO and the top of the cylinder l, which gasket is also engaged by the upper end of the bushing 8, so that when the cylinder-head is drawn into its position the gasket 33 will be compressed between the cylinder and cylinder-head for preventing the escape of pressure from the piston-chamber 2.

The piston, which is fitted to slide within the cylinder, is provided with a reduced shank 84, depending from the hollow pistonhead 9.- A rod 35 is secured rigidly within the said shank 34 of the piston and projects upwardly therefrom through the bore 36 of the piston-head and through holes in the gasket 33 and cylinder-head lO. A connectingdisk 37 is locked in position upon the upper end of the rod 35 by lock-nuts 38 30, which maybe adjusted to bring the connecting-disk 37 into proper relation with the contact-plates 2l 22. This connecting-disk 237 is completely insulated from the rod 35 by a sleeve i0, of any desired insulating material. This connecting-disk 37 is so adjusted that it will break contact with the contact-plates 2lA 22 when the piston approaches the limit of its inward or downward movement and will make contact with the contact-plates when the piston approaches the limit of its outward or upward movement. A spring 4I is interposed between the bottom of the bore 36 within the piston and the cylinder-head lO for positively returning the piston to the limit of its downward movement when pressure is withdrawn therefrom.

The bottom of the shank 34C oi' the piston is provided with a transverse groove 42 therethrough, so as to keep an open communication between the duct 7 and the interior of the piston-chamber even though the piston be at the limit oi' its downward movement.

As the piston is forced upwardly under fluidpressure the upper end of the piston-head will be caused to engag ethe gasket 33, and thus serve to seal the piston-chamber completely and prevent the leakage of pressure therefrom between the cylinder and cylinder-head. By thus making the piston automatically seal the cylinder the expense and care of making the piston-head S) an accurate ft in the bushing 8 are avoided.

To protect the connecting-disk 37 and contact-plates 2l 22, I provide a cap or cover I3, which is provided with depending portions il: 45, which lit between the lugs $30 and 2f) 31, respectively, for seating the cap firmly upon the cylinder-head IO. Screws 46 serve to removably secure the cap il in its position.

Yhen this switch is used in connection with a car-lighting system, it is operated by the pneumatic signal-pipe of the car, as follows: IVhen there is no pressure in the signal-pipeas, `for instance, when the locomotive is dctached from the train-the piston will be in its lowered position and the electrical connection broken through the circuit in which the switch is located. IVhen the locomotive is attached to the train and the signal-pipe is coupled up to the locomotive, the pressure oi' air within the signal-pipe will force the piston upwardly, thus completing the circuit. The circuit will be kept intact as long as there is pressure in the signal-pipe, and this is the period during which it is desired to keep the circuit unbroken.

It will be seen that the switch as above constructed is very simple and one which will withstand a great amount of hard usage, thus rendering it particularly applicable for use in connection with car-lighting systems. It will also be seen that the parts are well protected and the contact between the connecting-plate 37 and contact-plates 2l 22 will be always kept bright because of the frictional sliding movement ol' the connecting -disk along the inner faces of the contact-plates as the piston is raised and lowered. The structure is also materially simplilied by utilizing the bolts which secure the cylinder-head to the cylinder as binding-posts and vfor securing the contact-plates in position.

It is evident that slight changes might be resorted to in the form, construction, and arrangement of the several parts without departing from the spirit and scope o1 my invention. Hence I do not wish to limit myself strictly to the structure herein set forth; but

IVhat I claim isl. A iluid pressure controlled electric switch comprising a cylinder, contact-plates carried thereby, a piston itted to reciprocate in the cylinder, a connecting-disk exterior to the cylinder for engaging and disengaging the contact-plates, a rod for connecting the connecting-disk tothe piston and a removable cap for protecting the contact-plates and connecting-disk.

2. In a iluid-pressure-controlled electric switch, a cylinder, a cylinder-head, a packing-rin g interposed between the cylinder and cylinder-head and a piston iitted to reciprocate in the cylinder, the said piston being arranged to engage the packing-ring when at the limits of its outward movement-s for preventing the escape of pressure from within the cylinder.

IOO

IOS

IIC.

3. A fluid pressure controlled electric switch comprising a cylinder, a cylinder-head, contact-plates, bolts for securin the contactplates to the cylinder-head and the cylinderhead to the cylinder and a piston fitted to reciprocate in the cylinder arranged to engage and disengage the contact-plates as the piston is reciprocated.

4L. A fluid pressure controlled electric switch comprising a cylinder,a cylinder-head, contact-plates, bolts for securing the contactplates to the cylinder-head and the cylinderhead to the cylinder, a piston tted to reciprocate in the cylinder and a connecting-disk carried by the piston arranged to engage and disengage the contact-plates as the piston is reciprocated.

5. A fluid pressure controlled electric switch comprising a cylinder, a piston fitted to reciprocate therein, a cylinder-head, contact-plates, bolts insulated from the cylinder and cylinder-head for securing the contactplates, cylinder and cylinder-head together,

binding-posts carried by said bolts and a connecting-disk carried by the piston arranged to engage and disen gage the contact-plates as the piston is reciprocated.

U. A fluid pressure controlled electric switch comprising a cylinder, a hollow piston fitted to reciprocate therein, a cylinder-head, contact-plates carried thereby, a connectingdisk for engaging and disengaging the plates, a rod connecting the disk with the piston and a spring for normally returning the piston to the limit of its inward movement for positively disengaging the disk from engagement with the contact-plates when pressure is removed from the piston.

In testimony that I claim the foregoing as my invention I have signed my name, in presence of two witnesses, this 8th day of February, 1902.

XVILLIAM LORD BLISS.

Vitnesses:

FREDK. IiAYNEs, HENRY THIEME. 

